Messages in this thread | | | Date | Tue, 28 Sep 2004 20:31:03 +0200 | From | Joerg Sommrey <> | Subject | Re: nmi watchdog failure on dual Athlon box |
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On Tue, Sep 28, 2004 at 06:08:37PM +0100, Maciej W. Rozycki wrote: > On Tue, 28 Sep 2004, Joerg Sommrey wrote: > > > just tried Ingo's "lockupcli" nmi watchdog test - it fails to unlock the > > box. > > > > boot-parm: > > ...nmi_watchdog=2... > > The local APIC NMI watchdog has limited capabilities. It may fail to > trigger for certain lockups because there is no available event that would > happen periodically regardless of the CPU state. I can only suspect what > "lockupcli" does (where is it available from, anyway?), but if it runs > "cli; hlt", then the watchdog *will* fail.
Here's the quote from Ingo's mail: In <2Jo20-7ry-33@gated-at.bofh.it> Ingo Molnar <mingo@elte.hu> writes: |once the NMI watchdog is up and running it should catch all hard lockups |and print backtraces to the serial console - even if you are within X |while the lockup happens. You can test hard lockups by running the |attached 'lockupcli' userspace code as root - it turns off interrupts |and goes into an infinite loop => instant lockup. The NMI watchdog |should notice this condition after a couple of seconds and should abort |the task, printing a kernel trace as well. Your box should be back in |working order after that point.
[...]
|--- lockupcli.c | |main () |{ | iopl(3); | for (;;) asm("cli"); |}
Does this mean there is a good reason for further investigations on why the IO-APIC NMI watchdog doesn't work? Until now I thought it would be ok as long as the local APIC NMI watchdog is set up.
-jo
-- -rw-r--r-- 1 jo users 63 2004-09-28 18:42 /home/jo/.signature - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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